**5. Numeric Technique**

The nondimensional Equations (12)–(15) with boundary conditions (16) are solved by the control volume technique with the "SIMPLE algorithm". A nonuniform grid of 122 × 122 is taken to investigate the problem. The justification of the numeric code is very essential in the simulation. An internal code is tested against the available results for free convection of nanoliquid in a box [35] and it is shown in Table 1. Second, the problem of combined convection stream in a lid-driven box [36,37] is employed to compare the results of the current code (See Table 2). A good agreemen<sup>t</sup> among these results is obtained. Hence, the results offer a guarantee in the accuracy of the current computational code to inspect the problem.

**Table 1.** Comparison of *Nu* results for free convection of nanoliquids in a square box.


**Table 2.** Comparison of average Nusselt numbers for mixed convection in a lid-driven box.

